SNC2D – Earth and Space Science: Climate Change
Effects of Climate Change
(pp. 412-414, 415-416, 419-422)
(also from the David Suzuki Foundation website, http://www.davidsuzuki.org, accessed October 2009)
Climate change is already having a significant impact on ecosystems, economies and communities.
Rising average temperatures do not simply mean warmer winters. Some regions will experience more
extreme heat, while others may cool. Flooding, drought, and intense summer heat could result. Violent
storms and other extreme weather events could also result from the increased energy stored in our
warming atmosphere.
Area of Impact
1. Extreme Weather
2. Water Impacts
3. Forest Impacts
4. Imperilled
Ecosystems
5. Global Meltdown
Most Important Effects
SNC2D – Earth and Space Science: Climate Change
6. Health
7. Economic Risks
SNC2D – Earth and Space Science: Climate Change
1. Extreme Weather
Throughout the 10,000 year history of human civilization, weather patterns have remained
relatively constant. Though floods, droughts, storms and other extreme weather events have
always been a reality, they have been rare occurrences interrupting long periods of calm - sudden
outbursts of violence marring a gentle rhythm.
Now, because of human induced climate change, that gentle rhythm is breaking up.
The frequency of extreme weather events has increased steadily over the last century. The
number of weather-related disasters during the 1990s was four times that of the 1950s, and cost
14 times as much in economic losses. The economic toll from extreme weather events in Canada
in recent years has been significant, examples include Hurricane Juan in Halifax ($200 million),
the 2003 summer wildfires in British Columbia and Alberta ($400 million) and the 20012002 droughts which impacted much of the country ($5.8 billion reduction in GDP).
These trends confirm the predictions of computer models: as the atmosphere warms, the climate
will not only become hotter but much more unstable.
SNC2D – Earth and Space Science: Climate Change
2. Water Impacts
Water
Climate change will seriously affect water resources around the world. Changing water levels,
temperatures and flow will in turn affect food supply, health, industry, transportation, and
ecosystem integrity.
Ontario’s quarter-million lakes and countless rivers and streams hold about one-third of the
world’s fresh water. The province’s 11 million people rely on these waters, as well as on
groundwater and rainfall, for drinking, agriculture, and industrial uses. Forty-five percent of
Quebec residents take their water from the St. Lawrence River, which flows from the Great
Lakes. Projected changes in rainfall, evaporation, and groundwater recharge rates will affect all
freshwater users.

Lake levels are expected to decline in both inland lakes and Ontario’s four Great Lakes, as
more moisture evaporates due to warmer temperatures and less ice cover.

Reduced summer water levels are likely to diminish the recharge of groundwater, cause small
streams to dry up, and reduce the area of wetlands, resulting in poorer water quality and less
wildlife habitat.

Climate change will also mean an increase in the frequency and severity of droughts and
flooding.
Glaciers
Glacial melting is one of the most striking and visual signs of the impacts of climate change.
During the last century, the southern Canadian Rockies have shown remarkable loss in glacial
cover.
In B.C.’s Glacier National Park, scientists believe more than 50 per cent of the glacier ice has
melted away in the last century – enough melted ice to fill a reservoir at least five kilometres tall
by five kilometres wide.
Fact: Scientists estimate that globally glaciers are losing 92 cubic kilometres of ice per year –
that’s as much water used by Canada’s homes, farms and factories over six years.
Glaciers store snow like bank accounts store money – they hold snow in the winter and release
water when it’s most needed, during hot dry summers and periods of drought. However, global
warming is cashing in on a bank account that has been built over thousands of years but isn’t
being replenished.
Annual water flows from glaciers are diminishing, as less ice remains every year. Late summer
flows of the Mistaya River in Banff National Park have decreased 39 per cent over the last 50
years alone. Experts say that communities as far as 3,000 kilometres from the mountains – such
as those on Hudson Bay – will be affected in the decades to come if warming continues.
SNC2D – Earth and Space Science: Climate Change
3. Forest Impacts
Climate change is threatening the health of forests around the world. As temperatures rise,
weather patterns and the availability of water also change, altering the ability of trees to survive.
This could force forest types to shift their ranges faster than they may be able to.
In Canada, forests cover almost half of the landmass and make up 10 per cent of the world’s
forest cover. Forests are a crucial part of Canada’s natural heritage, wilderness areas and
economy
Although more in carbon dioxide in the atmosphere may encourage tree growth, the negative
impacts of climate change are expected to far outweigh any benefits.
Forest dispersion and shifting
Canada forests are expected to be among the most vulnerable in the world to climate change
because temperatures are expected to increase more in the Arctic, bringing with it changes in
precipitation. Although scientists do predict an increase in precipitation, it will likely not be
sufficient to keep up to increased evaporation for rising summer temperatures – leading to
decreased soil moisture. This will cause more drought-resistant trees or grasslands to replace
existing forest ecosystems.
During the last 50 years, summer temperatures frequently exceeded the critical threshold of the
most valuable timber species of the North American boreal forest, the white spruce. Over the
coming decades, scientists predict continued hot summer temperatures associated with climate
change would force this species into sharp decline, potentially to extinction.
Rising treelines
The alpine treeline is one of the most distinctive habitat transitions, separating continuous
subalpine forest from the alpine environment.
Treeline elevation is determined by growing season temperature. As global temperatures rise,
treelines are expected to advance upslope, shrinking the alpine environment (e.g. invading alpine
meadows) and fragmenting wildlife habitat. Climatologists believe that a rise in global
temperatures of 3.25 degrees Celsius would be equivalent to an ecological shift upwards of about
500 metres in altitude. Alpine species confined to the tops of low-lying mountains risk extinction
as the habitat is taken over by forests.
Forest fires
Hotter, drier summers are expected to increase evaporation and generally worsen the severity of
fire seasons and increase the risk of forest fires across most of Canada.
According to the government of Canada, both fire frequency in Canada’s boreal forest and total
area burned have increased over the last 20 to 40 years.
Forest disease and pest infestations
Warmer temperatures are also expected to expand the ranges and enhance the survival rates of
forest pests such as the spruce budworm and the mountain pine beetle.
Infestations of the mountain pine beetle are normally controlled by intense cold snaps in the
winter, but warmer winters have been one of the factors enabling the infestation to grow into an
epidemic in British Columbia’s interior forests. Over the next 10 years 80 per cent of B.C.’s
mature pine forest is expected to be lost due to the infestation of the mountain pine beetle.
SNC2D – Earth and Space Science: Climate Change
4. Imperiled Ecosystems
Climate change is altering the pattern of life on the planet, causing widespread species
extinction, migration and behaviour changes.
A changing climate forces plants and animals to migrate in order to survive. However, research
has shown that most plant species are able to migrate at only one tenth of the speed required to
keep up with human-induced climate change.
To make matters worse, human settlements and infrastructure have already subdivided
ecosystem habitat into isolated patches. Climate change will make many of these patches
uninhabitable for the species that live there, and they will be unable to escape. Northern
countries like Canada are experiencing some of the most serious impacts on biodiversity:

Canada's increasingly dry Northern boreal forests, stretching across the Canadian shield,
have seen burns go from 1 million hectares to 3 million in the last decade.

Female caribou migrate in spring to small pockets of vegetation where they feed and raise
their calves. But for the last 10 years, spring has come so early that by the time the caribou
reached the coastal plain, their principal food plant had already gone to seed.

A receding Arctic icecap and earlier than normal breakup of sea ice has affected polar bears,
which depend on sea ice to hunt seals. Recent studies showed polar bears in some regions
were down a third in body weight. The latest generation of seals was also found to be much
thinner than usual.
SNC2D – Earth and Space Science: Climate Change
5. Global Meltdown
Glaciers, ice sheets and Arctic ecosystems will be severely affected by climate change.
Glaciers around the world are already shrinking, threatening wildlife and freshwater supplies.
Global climate models predict extreme warming in the arctic if greenhouse gas emissions
continue to rise. Meanwhile, warmer ocean temperatures will transport large amounts of heat to
coastal Antarctica. Local impacts will be severe, but these changes will be felt throughout the
world.
Arctic Thaw: In the arctic, warmer temperatures will bring a loss of sea ice and permafrost,
disrupt ecosystems and traditional lifestyles, as well as wreak havoc with modern infrastructure.
Collapsing Ice Sheets: Enormous land-based ice sheets perched near the poles appear to be
vulnerable to human-caused climate change. If these ice sheets collapse, adding their bulk to the
oceans, sea level could rise by many metres in a matter of centuries.
Melting Mountains: The extraordinary Canadian alpine wilderness is threatened by climate
change. Ecosystems will undergo severe upheaval, challenging their ability to adapt,
while shrinking snowpack will reduce the freshwater supplies humans depend on.
SNC2D – Earth and Space Science: Climate Change
6. Health
Human health will be strongly impacted by climate change. As climate change brings tropical
weather to higher latitudes, tropical diseases - like the West Nile virus - will follow. Ecosystem
disruption will make the outbreak of water-borne diseases more likely.
Air pollution, which in Canada is largely caused by fossil fuel use, is already a scourge on public
health. Climate change will make smog more intense, and lead to still higher rates of asthma and
heart disease. The most devastating casualties will be among inhabitants of poor countries, where
there is little infrastructure to deal with changing water tables and increased extreme weather.
Among the world's least privileged, the potential for climate induced disaster is
SNC2D – Earth and Space Science: Climate Change
7. Economic Risks
The Intergovernmental Panel on Climate Change predicts damage caused by climate change
could cost developed countries up to 2 per cent of GDP. For Canada, a country highly dependent
on natural resources, this figure would likely be much larger.
We're already seeing ominous changes:

Rising ocean temperatures on Canada's West Coast have weakened economically valuable
salmon species, reducing the survival rates of spawning fish, scientists say. During the 1997
Fraser River sockeye run, mortality rate was 76 per cent, compared with a typical average of
5 per cent.

Forests in British Columbia were devastated in 2001 by the spruce pine-beetle, which thrived
thanks to unusually mild winters. An estimated 500,000 hectares of timber worth $4.2 billion
was infested, according to the BC ministry of Forests.

The 2001 prairie drought cost the Canadian economy over $5 billion in agricultural losses,
according to a University of Manitoba study.
In the future, Canadians may also expect the following:

Increased forest fires could turn large portions of Alberta's aspen parkland and boreal forest
into grass and shrubland.

Higher temperatures, dryer soil and increased insect infestation are expected to reduce crop
yields in much of the prairies by up to 30 per cent, according to Environment Canada studies.
Internationally, insurers are feeling the costs of climate change. Before 1988, the global
insurance industry never had claims for more than US $1 billion in any single natural disaster.
Yet between 1988 and 1996, 15 such events occurred, and a number of insurance companies
closed down in the wake of these disasters.
According to the Munich Reinsurance Corporation of Canada, "Economic losses caused by
natural catastrophes are likely to bring home the effects of climate change more and more
dramatically as time goes by."
Nonetheless, economic opportunities can be found among the solutions to climate change.